Sentence examples for who sent from inspiring English sources

The phrase "who sent" is correct and can be used in written English.
It is typically used to ask for the identity of the person who sent something, or to refer to the sender of a message or item. Example: "Please tell me who sent this package." (asking for the name of the sender) "I received a letter yesterday, but I'm not sure who sent it." (referring to the unidentified sender) "Who sent the email with the important documents?" (asking for the sender's name).